Switching device.



B. G. LAIVHVIE & J. L. McK. YAHOLEY. SWITCHING DEVICE. APPLICATION FILED 0CT.31| 1913.

1,138,673. Patented May 11, 1925:

' *m'massts; 8 I GLINVENTORS 6/1/0021 amme I 9. Job/11.. Mh. Yard/e y sv f i Y I; {ATTORNEY ,UNITED STATES PATENT OFFICE;

BENJAMIN G. LAMME AND JOHN L. McK. YARDLEY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A GOR- PORATION OF PENNSYLVANIA.

swrrcnme DEVICE.

. 1,138,673, Specification of Letters Patent. Patented May '11, 1915.

Application filed October 31, 1913. Serial No. 798,507.

T ll wh it mayponggm: the simple rotary converter, especially as re- Be it known that W6,'BENJAMIN G.LAMME gards armature reaction. In operating the and J OHN L. MCK; YARDLEY, citizens of the combined machine, the excitation of the field United States, and residents of Pittsburgh, coils of the booster may be reversed, thereby 5 in the county of Allegheny and State of causing the. generated voltage to raise or Pennsylvania, have invented a new and uselower the voltage impressed at the collector ful Improvement in Switching Devices, of rlngs. When the field is excited so that the which the followin is a specification. v ltage'g nerated bucks the impressed Our invention re ates to switching devices, voltage, the booster acts as a motor; when 10 and it has special-reference to automatically the field is excited so that the voltage genoperated switching devices to be employed erated boosts the impressed voltage, the

. preferably in connection with the operation booster acts as a generator. In the former of synchronous booster rotary converters. case, the rotary converter, being partially The object of our invention is to provide a driven by the booster, delivers some of its 15 simple, reliable and effective automatic direct current energy as a generator. The

means for overcoming certain difliculties additional generative or direct current arthat have been encountered in maintaining mature reaction present under the brushes correct commutatingconditions on machines by reason of this generator action of the rofth b -i di t d character. -tary, is, therefore, additively combined with .20 By synchronous booster rotary conthe generative reaction of the simple converter we mean a machine combining a roverter. On theother hand, in the latter case, tary converter and a mechanically associated Where the booster is acting as a generator, alternating current booster which have their being driven by the converter acting parrotor windings connected in series circuit ret ally as a motor, the motor action of the 25 lation. The preferable design disposes both Simple. converter is, correspondingly wigconverter and booster on a singleshaft. The merited, and the additional motor or alterfield frames are adjacently mounted on a nating current reaction in the commutating common bedplate and the series rotor con f e, lng 1n opposition tot-he above-mennections are permanent, there being no slip tloned generative reaction of the simple con- 30 rings on the converter proper. The purpose erter in this zone, .is, consequently, subof the combination is to boost or buck tracted therefrom. the incoming alternating current voltage for From the foregoing theoretical considermaintaining a predetermined direct current ations, it will be seen that the commutatvoltage on the converter. ing field strength of the synchronous booster 35 The total armature reaction of a rotary rotary converter .must fulfil two requireconverter, that is, the resultant-reaction obments in order to successfully maintain tained by integration around the entire argood commutating conditions; first, the mature circumference of the reacting effects field strength must vary with the load curof both the alternating and direct currents rent of the converter proper; and second,

40 present during operation in the armature the field strength must vary according to coils, is normally that of a motor, or, in the additional armature reaction introduced other words, the alternating current reacby the active operation of the booster, which tion predominates. However, if we take vreaction may be either positive or negative, simply'the commutating zone, that is, the reas hereinbefore described. Heretofore, the

45 gion directly beneath the commutator first recited requirement has been recogbrushes, Which,regi0n is,'of course, all that nized and fulfilled by means of a series we areconce1'i1ed with when considering commutating field winding connected in commutating cpnditions, it has been shown the main line, thus having load current flow-' mathematically and proved by tests that the ing through the winding at all times. The

50 normalreaction, in this zone is that of a gensecond requirement, however, has caused erator, or, to state it differently, the directv considerable difliculty and the attempts current reaction is the greater. 1

The synchronous booster rotary converter has different electrical characteristics from made to attain the desired result have been moreor less unsatisfactory.

Accordi,ng to our present inventjtongiwe armature reaction provide a method for fulfilling both prescribed requirements. series commutating field winding is provided for varying the coinmutating field strength in proportion to the load current; and an auxiliary commutating field nected in series circuit relation with the shunt field winding of the booster, is em ploycd for varying the commutating field strength in proportion to the additional caused by the motor or generator effect previously referred to, as will be understood from the following statement: The additional armature reaction "1 hereinbefore considered is proportional to i the additional alternating or direct currents flowing in the rotary converter armature upon excitation of the booster, and, conse quently, the reaction in question bears a readily determined relation to the field current of the booster. The pioneer system embracing the above principles is fully set forth in the co-pending application of J. L. McK. Yardley, Serial N 0. 757,379, filed March 28, 1913 and assigned to the Westinghouse Electric and Mfg. Co. However, under light load conditions, it has been found that the converter, when connected as above, is sometimes over-compensated particularly with maximum bucking action by the booster voltage, and is occasionally undercompensated especially with maximum boosting action by the booster voltage; that is, the commutating field may be either too strong or too Weak, and sparking at the brushes may result. \Ve therefore provide automatic means dependent upon load conditions for inserting in circuit or shortcircuiting the commutating shunt field winding or any portion thereof. Naturally, this procedure by itself Would-change the resistance of the circuit under consideration: consequently, an undesirable value of current would flow in the booster field circuit and poor voltage regulation and commutating conditions on the converter would ensue.

e, therefore, also provide means controlled by the-said first means for automatically inserting in, and excluding from, the circuit a suitable resistor for maintaining approximately the same total resistance in the booster field circuit as before, simultaneously With the short-circuiting and the in-- clusion, respectively, of the auxiliary commutating field winding or portion thereof. In this way, substantially correct commutating conditions are automatically maintained on the rotary converter.

In the accompanying drawing, the single figure is adiagrammatic view of a combination dynamo-electric machine associated with an automatic switching device constructed in accordance with our invention.

Referring to the drawing, a rotary converter 1 is mechanically associated withan winding, which is conalternating current booster 2 by means of a shaft 3, and the rotor windings (not shown) of the two machines are connected'in series circuit relation, as hereinbefore stated. A plurality of conductors 4 serve to connect the booster rotor to a suitable alternating current supply circuit (not shown). The booster 2 has a shunt field winding 5. The converter 1 is provided with a main shunt field winding 6 which is connected in series with a suitable rheostat 7 across the direct current terminals 8. In addition, the converter has a series commutating field winding 9 suitably connected in the main line, and a commutating shunt field and main auxiliary shunt field winding 11 and 12, respectively, which are connected in series circuit relation with the booster field winding 5, a resistor 13 and a reversing rheostat 14 across the direct current terminals 8. An automatic switching device 15 is associated with the last recited series circuit and comprises an auxiliary relay 16 and a main bridging member 17 that may be actuated thereby and that is adapted, in accordance with circuit conditions hereinafter described, to assume two different positions in which the member 1 respectively short-- circuits the commutating shunt field winding 11 and the resistor 13.

The relay 16 comprises movable and preferabl biasedbridging contact members 18, a coil 19 connected in series with a variable resistance 20, preferably across one-half of the series Winding 9, for actuating the members 18 under predetermined conditions, and a pair of coils 21 and 22 for actuating the main brid ing member 17 according to the position of the movable contact member- 1S. The coils 2.1 and 22 are severally connected across the direct current terminals 8 through gaps or openings 23 in the respective circuits, which gaps are adapted to be separately bridged by the contact members 18.

It will be understood that the purpose of the variable resistance 20 is to permit of adjustment of the action of the coil 19 upon the members 18 to correspond to the particular ope-ratio g conditions.

Assuming that the machines 1 and 2 are operating under light-load conditions and that the parts of the switching device 1b 0c cupy the positions shown, the coil 22 being energized through the upper contact member 18 which is biasedto the lower position and the commutating shunt field winding, consequently, being short-circuited by the. bridging member 17, the operation of the apparatus shown is as follows: When a predetermined load current has been attained, the voltage across the corresponding half of the series winding 9 will be high enough to send a surlicie-nt current through the coil 19 to cause the contact members 18 to move to their other position, whereupon the coil 21 is energized through the lower member 18 and the'bridging member 17 is, tracted to its other position,

consequently, atthus operatively sorting he commutating shunt field winding 11 in'the circuit and simultaneously short-circuitin the resistor 13. The total commutating eld strength will then be aucompensate for the changes i It will tomatically maintained at a proper value to in armature reaction of the converter, as hereinbefore dewhichcaused the above-indicated actuation of the-members 18, the device 15. will automatically reassume the position shown in the drawing, the'winding 11 being shortcircuited and the resistor 13 being included inathe circuit.

' "Wedo not wish be restricted the specircuit connections and details of conl-zdesire thatonly 'ruction herein set forth, as many variations-thereof may be made within the spirit our invention. We, therefore,

such limitations shall be imand scope. of

posed as are indicated in the appended claims.

' sociated We claim as our invention: ,1. The combination with a plurality of dynamo-electric machines mechanically asand electrically connected in series circuit relation and provided with field magnet windings,of a circuit including certain ..1 of the windings of both machines, automatic means for eliminating a predetermined part of said circuit and means associated with 'said first means for simultaneously maintaining substantiallyvconstant electrical resistance in said circuit;

m 2.- The combination with a-plurality of dynamo-electric machines mechanically asi sociated circuit relation and provided with field magnet windings, of a circuit including certain of the windings of both machines, automatic means for eliminating one of said windings from said circuit under predetermined conditions, and means dependent upon said first means for maintaining the total resistance of said circuit substantially constant.

' 3Q The'combination with a dynamo-electric machine adapted to deliver alternating and direct current and-provided with a plurality of field windings, and a. second dyna-' mo-electric machine mechanically associated with said first machine and electrically conminted in series therewith and provided with a? field winding which is connected in series circuit with one ofthe field windings of so;

' -means said -w1ndings for eliminating a certain said first machine, ofa resistor, automatic dependent upon the current in one of Winding from said series circuit, and means 'for thereupon inserting said resistor in said circuit.

be understood-that, when the load current drops back. to a value below that and electrically connected in series- 4. The combination with a dynamo-electric machine adapted to deliver alternating and direct currentsand provided with a series field and a plurality of shunt field windings, and a second dynamo-electric machine mechanically associated with said first ma chine and electrically connected in series therewith and provided with a shunt field. winding which is connected in series circuit with one of the shunt field windings'of said first machine, of a resistor having a resist ance substantially equal to that of one of said shunt field windings, a switching device for eliminating that winding from said se circuit with the auxiliary shunt field winding ofsaid first machine, of a resistor hav-' ing a resistance substantially equal to that of said auxiliary shunt field winding, a switching device biased to short-circuit that winding and include said resistor in said series circuit, meansassociated with said device for opening the short-circuit and simultaneously eliminating said resistor, and a coil connected across a portion of said series field winding and dependingjupon the current therein for actuating said switching device i'rom its biased position.

6. The combination with a dynamo-electrio machine adapted'to deliver alternating and direct current and provided with a main field winding and auxiliary series and shunt field windings and a second dynamo-electric machine mechanically associated with said first machine and electrically connected in series therewith and provided with a shunt field winding which is connected in series circuit with the auxiliary shunt field winding of said first machine, of a resistor hav ing a resistance substantially equal to that of said auxiliary shunt field winding, a multi-position switch for short-circuiting either said auxiliary shunt field winding or said resistor, a plurality of electromagnetic .Y

means for severally positioning said switch upon energization, a circuit-closing member biased to cause a short-circuit of said auxiliary shunt field winding, and a coil connect-- ed across a portion of said series field winding and dependent upon a predetermined increase of current therein for actuating said circuit-closing member to cause a short-circuit of said resistor.

7. The combination with a rotary con verter provided with a main field winding and auxiliary series and shunt field windings, and an alternating current booster mechanically associated with said converter and electricall connected in series therewith and provided with a shunt field winding which is connected in series circuit with the auxiliar shunt field winding of said converter, 0 a resistor having a resistance substantially equal to that of said auxiliary shunt field winding, a multi-position switch for short-circuiting Jeither said auxiliary shunt field Winding or said resistor, a plurality of magnet coils severally adapted, upon .energization, to actuate said switch to its various positions, a movable contact member biased, under light load conditions, to energize the magnet that causes a short-circuit of said auxiliary shunt field Winding,.

and a coil connected across a portion of said series field Winding and dependent upon a predetermined increase of current therein for actuating said contact member to deenergize the previously energized magnet coil and to simultaneously energize the other magnet coil to short-circuit said resistor.

8. The combination with a dynamo-electric machine, of a booster therefor, a field circuit including the main field Winding of the booster and a commutating field winding of the dynamo-electric machine, and

means for shunting said commutating field winding out of said field circuit and for simultaneously inserting a resistance element therein of such value that the total resistance of said field circuit remains substantially constant.

.9. The combination with a dynamo-electrio machine, of a booster therefor, a field circuit including the main field Winding of the booster and a commutating field winding of the dynamo-electric machine, means for reversing the direction of current How in said field circuit, and means responsive to the load for shunting said commutatin field winding out of said field circuit and tor simultaneously inserting a resistance element therein oi such value that the total resistance of said field circuit remains substantially constant.

In testimony whereof, we have hereunto subscribed our names this 18th day of Oct.,

' BENJ. is. LAMME. J OHN L. McK. YARDLEY. Witnesses:

B. B. Hines, M. C. Mnaz. 

